Hello!

[red91sit]

Hello Everyone!!

I'm a huge engineering fan, and found lots of very inspirational and creative people on this site. That's what made me decide to register and hopefully gain some insight from alll of you.

I have several vehicles, and in the past, have owned even more. I've never driven anything overly fuel efficient, but I I do enjoy anything automotive. Trying to get the best gas mileage is just as fun for me as getting the perfect slide, or the fastest corner.

My most recent idea is based upon test data located HERE
According to them, the 1984 Ford Thunderbird requires only 15 h.p. to go 50mph. It seems like if we could somehow hook up another engine in the trunk of a FWD car (It shall be named the "highway" engine) that only has about 25 horsepower, we could turn the main "acceleration" engine off in neutral and cruise around on those 25 horsepower. Should the need to pass occur, the main engine could be restarted and give plenty of thrust.

I dunno seems like a good idea to me, even if it was just one test vehicle doing it.

[onegammyleg]

Hi red91sit - ¨the 1984 Ford Thunderbird requires only 15 h.p. to go 50mph.¨

I dont know about that exact figue fo rthat car , but it is true.
A car needs only a small portion of the power the engine can produce to keep it at cruising speed.
And it is quite logical , when you are cruising you are only using a very small amount of throttle.
An engine with a small throttle opening is only making a small amount of power.

I didnt read that LINK , but it is possible that a 15Hp engine from a smaller machine could go into that car and it woudl drive up to 50mph.

Unfortunately acceleration will be quite slow.- but FE wil llikely be better getting 15hp out of that small engine compared to geting 15HP out of the bigger standard engine. (untill you get to the hills- then FE will suk)

[SVOboy]

Hey red! Welcome to the site. Great to have someone with ideas like this, I don't think we've considered it before. So yeah, feel free to stick around and we'll see what we can learn together!

[Ted Hart]

Originally Posted by red91sit

Hello Everyone!!

I'm a huge engineering fan,



the 1984 Ford Thunderbird requires only 15 h.p. to go 50mph. It seems like if we could somehow hook up another engine in the trunk of a FWD car (It shall be named the "highway" engine) that only has about 25 horsepower, we could turn the main "acceleration" engine off in neutral and cruise around on those 25 horsepower. Should the need to pass occur, the main engine could be restarted and give plenty of thrust.

Hello, "fan"!
There is a problem with your idea...it's called torque.
The T-bird takes so many foot-pounds of torque (at 15 HP) to cruise at 50 MPH ; can the smaller "trunk engine" crank out this same torque at this same RPM(50 MPH)? I rather doubt it... not having the same piston area(s) or crankshaft journal off-sets. HP has nothing to do with doing work(torque)...it is the rate of doing this work!
Hope this helps! -Ted Hart

[omgwtfbyobbq]

That's a pretty good idea. The only problem would be that it's risky, brake vacuum's off of intake vacuum, but you can always switch to vacuum booster brakes. PS isn't needed at highway speeds imho, and as for lack of torque, that's what gears are for. 15hp at some rpm is 15hp at some rpm is 15hp at some rpm. Power is power, just make sure to gear the motor right and you're set.

[onegammyleg]

?I rather doubt it... not having the same piston area(s) or crankshaft journal off-sets. HP has nothing to do with doing work(torque)...it is the rate of doing this work!?

Fortunately the torque multiplication of gear ratios would make up for an engine plant that lacks torque. (within limits of course)

[Matt Timion]

Originally Posted by omgwtfbyobbq

PS isn't needed at highway speeds imho

You're right. In fact I think it's better to disengage PS at high speeds. It will most likely decrease the chance of losing control.

In a perfect world we could design a car that would disable power steering and lower itself a few inches at highway speeds.

[omgwtfbyobbq]

I test drove a... suzuki(?), something a couple years ago and it had speed sensitive power steering... so nice. I think I'd just take it out all together and muscle it, but with the SSPS, driving at highway speeds w/o the twitchyness is nice. Better yet, get a Insight with a dead pack and bag it!

[red91sit]

My first car actually had powersteering clutch style setup on its' powersteering where it turned off at X speed, the change was completely unnoticeable, and road feel was excellent. I ended up just taking it off alltogether for increased road feel.

BTW- I've actually got a 37 hp 4cylinder motorcycle just sitting in my garage. I'd love to hook it up to a rear wheel on my civic, perhaps mounting it right along side the brakes? It has a 6 speed transmission on it right now, so I'd have plenty of room to play with that. Since it's from a motorcycle the chain drive would help make motor placement more flexible by using longer/shorter chains to get correct tension.

The whole Torque - Horsepower discussion. Horsepower is the product of torque and rpm, (TQ. X RPM)/5252. If the two don't cross each other at 5252 rpm, the dyno charts a fake. Therefore I find the measure of torque rather unimportant for this particular excersize.